@tom's script was written for Apple Mail which is very different from MS Outlook (2011 and 2016). So it's not surprising the script quickly failed.
I've been playing with a script for Outlook 2011, and it works, but I'm not happy with how the results look when I paste into another app, although TextEdit is OK. I'm working on another option to put encoded HTML on the clipboard as well, and hope that looks better.
But if you want the best results, I've found just create a PDF from Outlook when you go to print the message. This provides all the data, and looks great.
Until I have something better, good luck.